1. Field of the Invention
The present invention relates to a camera for receiving data signals from an external information reading and transmitting device.
2. Description of the Related Art
Commonly assigned Japanese Patent Application No. 01-132769, filed May 29, 1989, and U.S. patent application Ser. No. 530,190, filed May 29, 1990, disclose a camera system in which information necessary for photographing, for example information written on a photographic sample storage medium using a bar code or the like, is read by an information reading device. The read data are transmitted to a camera using infrared light. The data are received by an infrared photosensor built in the camera, and photographic program operations are automatically switched according to the received data. Thus, even a person who does not know the effect of changing the diaphragm, shutter speed, and the like on a photograph can perform an optimum photographing operation.
Since the data are received in the form of infrared light, it is necessary to convert and amplify the detected signal to a signal of a type and level capable of being detected by a control unit of the camera. In conventional cameras, it is necessary to always supply current to the amplification circuit (since it is uncertain when the data will be transmitted), which consumes a considerable amount of current. Such cons;rant current consumption is not desirable in a camera, or the like, which uses a battery for its power supply. Accordingly, a conventional camera must have a configuration wherein data are transmitted only after the camera has been placed in a state in which the data can be received according to a certain operation, and current is not supplied to the amplification circuit in any other state.